For an artificial tooth (i.e. "dental restoration") to closely replicate the lost natural tooth that it replaces, the artificial tooth must emerge from the gum tissue with the same shape and contour as did the natural tooth. Currently, dental implants, which function as artificial tooth roots, are embedded in the bone tissue of the maxillary and mandible. After these implants have osseointegrated, it is necessary to form the gingiva overlying the bone where the implant is installed. Healing components function to expand a transmucosal opening from the round shape of the implant to a size that more nearly approximates the size of the tooth where it emerges from the gum. After the healing components form the gingival tissue, an impression component is used to make a model of the patients mouth in the area of the implant site.
Creating an artificial tooth for a patient who has been fitted with one or more dental implants begins with taking this impression of the patient's case. Dental implants have locking means (usually a hexagonal boss) useful to interlock with corresponding locking means in the components fitted to them when it is desired to prevent rotation of a component relative to the implant around the longitudinal axis of the implant. Once an implant has become osseointegrated with the host bone, it becomes necessary to preserve in the impression the information describing the orientation of its hex. Recording the correct hex orientation is critical if an accurate model of the patient's case is to be created in the dental laboratory. The component used to effect this information transfer is commonly called an "impression coping".
By its very nature the impression material is resilient and soft enough that it can be removed from the patient's mouth after it has set up, yet firm enough that it can preserve information imparted to it by an impression coping. If the coping used is a transfer type impression coping, it will remain in the patient's mouth when the impression material is removed, pulling the transfer coping out of the socket formed around it in the impression. This technique is known in the art as the "closed tray method". If the coping used is a pick-up type impression coping, it will remain within the impression when the material is removed from the patient's mouth. This technique is known in the art as the "open tray method."
A problem that exists with current impression components is that components used for pick-up type impression coping cannot be used for transfer type impression coping and vice versa. This forces manufacturers to produce two separate lines of impression coping components--one for pick-up type and one for transfer type. Moreover, clinicians are forced to maintain separate inventories of components to be used with either method.
Therefore, it is an object of the present invention to provide an impression coping component which may be interchangeably used with either pick-up type or transfer type impression coping methods.